Lumbar plexus block with ultrasound-guided shamrock technique: In-plane versus novel out-of-plane approach

Lumbar plexus block (LPB) can be used with different techniques for anaesthesia and postoperative analgesia during femoral surgery. This study aimed to compare in-plane and out-of-plane methods using the Shamrock technique.

Forty-two patients scheduled for surgery due to femoral neck fractures were included in this randomized controlled study. The Shamrock technique was used to visualise the lumbar plexus. Patients were randomized to 2 groups: one group received LPB using the in-plane technique (IP group, n = 20), and the other received LPB using the out-of-plane technique (OOP group, n = 20). The primary outcome measure was block procedure time. Secondary outcomes included the number of needle insertions and redirections, needle depth (cm), minimal nerve stimulation (mA), sensory and motor block levels, and epidural spread.

No statistically significant difference was found between the groups in block procedure times (p > 0.05).The number of insertions and the number of needle redirections were significantly lower in the OOP group compared to the IP group (p = 0.005). The needle depth was significantly greater in the IP group compared to the OOP group (6.5 ± 1.1 cm vs 5.1 ± 0.8 cm, p = 0.001). No difference was found in sensory and motor block times (p > 0.05). No differences were observed in the number of patients with epidural spread or in the incidence of complications (p > 0.05).

The OOP technique demonstrated similar efficacy to the IP method using the Shamrock technique. The OOP technique can be used as an alternative for elderly patients in whom the IP technique can be difficult.